Pharmacology for Dentistry

290 Section 8/ Drugs Acting on Endocrine System

axilla, chest and pubic hair and change in voice;
development of accessory sexual organs e.g.
seminal vesicles, prostate and epididymis and
development of male skeletal musculature.

Androgens and anabolic steroids are
classified as in table 8.3.4.

TESTOSTERONE

It is a natural androgen secreted by
testis. The secretion is regulated by LH
hormone secreted by pituitary gland.

It is responsible for development of sex
organs and secondary sex characters in
males at puberty. It leads to growth of
genitals, growth of hair (pubic, axillary,
beard, moustache, body hair), thickening
of skin, larynx grows and voice deepens
and also behavioural changes. It is also
needed for normal spermatogenesis and
maturation of spermatozoa. It is also
responsible for pubertal spurt of growth in
boys leading to increased bony and skeletal
muscles growth.

Pharmacokinetics

Testosterone is not given orally as it is

extensively metabolised in liver and the

bioavailability is low. Testosterone is

converted by 5a-reductase in target tissues

to more potent dihydrotestosterone.

It is metabolized in liver to glucuronic acid

and sulfate conjugates and excreted in urine.

Adverse effects include menstrual

irregularities, deepening of voice in women,

edema, cholestatic jaundice, virilization,

priapism, increased libido, acne, precocious

puberty, premature epiphyseal closure,

gynaecomastia and hepatic carcinoma and

reduction in spermatogenesis.

The capacity of androgens to enhance the

epiphyseal closure in children may persist for

as long as several months after discontinuation

of the drug. In children androgens should be

used with great caution.

It is indicated in replacement therapy to

maintain sex characteristics in adults with

Table 8.3.4: Classification of androgens, anabolic steroids and antiandrogens.

I. Natural

Testosterone (as propionate, cypionate Propionate 25-200 mg IM per day to bimonthly;

undecanoate, enanthate; NUVIR) undecanoate 40 mg OD-TDS

II. Synthetic

Methyltestosterone 25 mg/day SL

III.Anabolic steroids

Nandrolone (as decanoate, phenyl 10-100 mg IM once a wk to every 3 wks

propionate; DURABOLIN)

Stanozolol (NEURABOL) 2-6 mg/day

Mesterolone (PROVIRONUM) 25-50 mg/day

IV.Antiandrogens

Danazol (DANOGEN) 200-800 mg/day

Cyproterone acetate

Flutamide (PROSTAMID) 250 mg TDS